I recently posted a question about light-headedness after squats, and it was mentioned that squat sets should not be taken to failure.

I can appreciate squats could be dangerous if one collapsed or passed out without safety bars available. Bench presses one could drop the bar on themselves. Heck, what happened to this guy doing bicep curls?

But is it only safety concerns or are there other good reasons not to take sets to failure? For bicep curls for instance, my last full rep would take 10 seconds to get to the top, then the next one would fail maybe about 20% through the contraction despite my every effort (while maintaining form) to keep it moving. Total muscle failure. Is this not recommended?

I once read an article that said going to failure when working for strength is not recommended, but when working for mass there can be some benefits. When I'll find the article again I will post it as an answer.
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UsedtobefatDec 27 '12 at 0:25

Planning for a failure scenario can help you to do it safely. For example, do squats in a power rack or loaded with bumper plates and performed on a platform - in both cases you can fail safely. Obviously, you need to be aware of your body and dump the bar immediately if anything feels wrong.
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Greg♦Dec 27 '12 at 21:22

2 Answers
2

This depends entirely on how you are defining failure, as there are essentially two definitions, and it is crucial you understand the difference between the two.

Do as many reps as possible as literally possible and nothing less.

Do as many reps as possible to do while maintaining proper form.

If you are using the first definition then you are liable to run into massive trouble working out to failure. To begin with, your fail reps will be bad form which means at best you aren't working out your target muscles (think: using momentum during bicep curls) and at worst your form is setting you up for injury. This should quite obviously be avoided.

The second definition is where you want to focus, as you want to always maintain good form first and foremost throughout your entire set. If your form starts to give in the middle of that set, then your set is over and you need a rest or lower weight. I would also extend this definition to include effort necessary to safely rerack the bar (which can often be as much effort as a rep). This is the definition of failure that I use.

With higher weights there is always a safety concern with lifting just as you noted, but if you are taking the proper precautions there should be no worry about going to failure because you are using good form throughout.

As for the purpose of going to failure, there are really only two areas where it is useful:

Bodyweight exercises are often unable to be supplemented with added weights, so you must rely on added reps to progressively overload the body to gain strength.

When gauging your ability, doing reps to failure is a good measurement to use. For instance, I am doing three sets of 5 squats at 200 pounds. The first two sets I complete 5 reps easily. During the final set I go to failure and reach 15 reps. This is a cue that I am using a submaximal weight for my workout, and I may need to add a lot more weight.

Sets to failure help build mass. Typically, sets to failure is the domain of the bodybuilder where the primary goal is to increase the size of the muscle rather than to increase strength. You can gain strength this way, but the primary result is larger muscles.

By definition, when you go to failure, your form will start to degrade as you get later in the set, until you simply cannot lift the bar any longer.

Trade offs:

When strength is the priority failure should not be in your vocabulary. It hurts your confidence under the bar, and reinforces bad habits as your form degrades.

When mass is the priority, failure is the fastest way to larger muscles. It does come with serious DOMS pain, and it takes a week or two to fully recover. During recovery the muscle becomes pretty much useless.

If a bodybuilder were in a position where they could do reps to failure, wouldn't they be better off by just increasing the weight instead and sticking to their rep range?
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MosesDec 28 '12 at 17:33

If you primarily want size, you need to be targeting reps in excess of 8-12 (depending on upper or lower body work). As long as they can hit those rep ranges and beyond, increasing weight on the bar will improve those efforts even more. If failure is 6 or fewer reps, they won't be achieving their goals. I honestly think both strength and hypertrophy are important components.
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Berin LoritschDec 28 '12 at 18:07

@BerinLoritsch "in excess of 8-12"? Meaning more than 12? Or in the range of 8-12?
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nfwDec 31 '12 at 20:23

8-12 is a common rep range for mass, but you can also get good results taking it all the way out to 15-20 reps depending on upper body or lower body work. So 8-12 is the start of the range and 15-20 is the end of the range. Anything beyond that is primarily endurance.
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Berin LoritschDec 31 '12 at 22:28